The U.S. Air Force reported several incursions occurred in the past week at four bases where the American forces operate.

The drones were spotted between Wednesday and Friday near RAF Lakenheath, RAF Mildenhall and RAF Feltwell. They were actively monitored after they were seen in the vicinity of and over the three bases, U.S. Air Forces Europe said in a statement.

The government has warned that those behind recent drone incursions over US airbases will be "shown the full force of the law". Defence Minister Maria Eagle said it was "taking steps" after the mystery unmanned aerial vehicles (UAVs) were spotted over and around the three locations in Suffolk and Norfolk.

Since the first small unmanned aerial system was first spotted on Nov. 20, the number of drones has fluctuated and there have been a range of different sizes and configurations, said the U.S. Air Forces in Europe spokesperson.

Unidentified drones have been spotted flying over four bases used by the United States Air Force in Britain, prompting the British government to call in military staff to help protect the sites. The U.

The British military has increased security around four air bases in the country that are used by U.S. forces after "a number" of drones were spotted near them.

Unidentified drones have been spotted again over three British air bases used by the U.S. Air Force, officials confirmed Tuesday. The three bases are all located within the same area of eastern England between Cambridge and Norwich,